Are carbs really the problem?

In We’ve long blamed carbs for making us fat. What if that's wrong? Julia Belluz writes about a study that casts doubt on carbohydrate-insulin hypothesis, the theory that

... suggests that a diet heavy in carbohydrates (especially refined grains and sugars) leads to weight gain because of a specific mechanism: Carbs drive up insulin in the body, causing the body to hold on to fat and suppress calorie burn.